1. Field of the Invention
The present disclosure generally relates to wireless communications and more particularly relates to systems and methods for communicating with stations in standby mode in an encrypted environment.
2. Background Information
Among other things, FIG. 1 illustrates a typical network configuration for communicating data between stations via an access point in a wireless local area network (WLAN) or 802.11-based network. As illustrated in the non-limiting example of FIG. 1, a network 140 may be coupled to access points 130 and 132. In some embodiments, the network 140 may be the Internet, for example, and can be connected to an external computer such as central computer 150. Access point 130 can be configured to provide wireless communications to various wireless devices or stations 110, 120, 124. Furthermore, access point 132 can be configured to provide wireless communications to various wireless devices or stations 112, 114 and 116. Depending on the particular configuration, stations 110, 112, 114, 116, 120, and 124 may be a personal computer (PC), a laptop computer, a mobile phone, a personal digital assistant (PDA), and/or other device configured for wirelessly sending and/or receiving data. Furthermore, access points 130 and 132 may be configured to provide a variety of wireless communications services, including but not limited to: Wireless Fidelity (WIFI) services, Worldwide Interoperability for Microwave Access (WiMAX) services, and wireless session initiation protocol (SIP) services. Furthermore, the stations 110, 120, 124 may be configured for WIFI communications (including, but not limited to 802.11, 802.11b, 802.11a/b, 802.11g, and/or 802.11n).
Access point 130, for example, periodically broadcasts a beacon frame to various stations at a beacon period. The beacon frame is used by an access point to announce its presence and to relay information. For example, if station 110 is a laptop and is powered up or is transported to a location within range of access point 130, station 110 listens for a beacon frame from all access points in its range. Each access point within range transmits a beacon frame and depending on the system, the user at station 110 can select which access point to use, thereby making an association between station 110 and the access point.
In order to save power, stations can be put into standby mode or a deep sleep mode. Also, for the purposes of this disclosure the term “sleep mode” will be taken to mean an operating state entered by a computing device either upon initiation by a user or after expiration of a period of sufficient inactivity in which the amount of power supplied to the device is reduced as compared to the amount supplied during normal operation.
Due in part to the dynamic technology dependent nature of today's workplace, network administrators must constantly perform functions requiring access of individual network nodes from the administrator's computer. These functions can include configuring new nodes, updating and installing software, adding network printers, scanning for viruses, and file back-ups to name a few. Typically, many of these administrative functions are scheduled for execution after normal business hours so as to minimize interference with user applications during the work day. However, during these after hour times, individual computers on the LAN may be in one of a variety of power conserving modes, also known as sleep modes. Typically, the power conserving modes cause the display to be put in a low power state, the hard drive to be spun down and even the microprocessor to reduce its clock frequency or to be shut down completely. In the case where the computers are actually stations on a WLAN, the antenna and the radio frequency (RF) circuitry are shutdown or put into a power saving inactive mode. Having the computers powered down can make it difficult if not impossible to schedule and implement after hours network events. If the administrator has to physically turn on each machine, the efficiencies of centralized network administration are lost.
In another set of circumstances, if the wireless station has enabled a phone function perhaps in a voice over IP (VoIP) setting, the station may need to wake up to receive the call.
In U.S. patent application Ser. No. 10/995,188, filed Nov. 24, 2004, entitled “Systems and Methods for Wireless Wake-On-LAN for Wireless LAN Devices,” a wakeup data sequence is broadcast by an access point to all stations. Each station periodically wakes up and receives the wakeup data sequence, if present. The wakeup data sequence identifies which stations need to wake up. If a station receives the wakeup data sequence, but is not identified, it returns to standby mode.
When a station goes into standby mode, it is disassociated with the access point. In a protected environment, such as when Wired Equivalent Privacy (WEP) is used, the frame body of all data frames from the access point is encrypted. Because a station in standby mode is disassociated, it cannot decrypt data frames from the access point. The station will not be able to decrypt the body of a wakeup data sequence as broadcast by the access point. So even if the station were able to determine that there was a wakeup data sequence broadcast by the access point, the station could not decode the frame body and hence would not know which stations need to wake up. Accordingly, various needs exist in the industry to address the aforementioned deficiencies and inadequacies.